1. Field of the Invention
The present invention relates generally to an input control device for a personal computer. Still more particularly the present invention relates to a scroll bar control using a capacitive touch pad.
2. Background of the Invention
The complexity of functions performed by personal computers ("PC") has created a need for more sophisticated input and output devices for controlling the operation of the computer. For example, the mouse was developed to facilitate control of the movement of a cursor on the computer screen. Other input devices for controlling a cursor such as the track ball and joys tick are widely available.
Because of the limited size of a computer display, a computer operator typically can not view on entire document or spreadsheet on the display at one time. Rather, the operator must "scroll" through the document to view various portions of the document. Scrolling usually includes the ability to scroll up and down through a document, as well as left and right. Many software programs include one or more scroll bars to allow the computer operator to view various portions of the data not currently view able on the display. Thus, by implementing scroll bars, word processing and spread sheet programs, for example, allow entry and viewing of more data than can be seen on the display at any one point in time. Referring to FIG. 1, a typical word processing program 112 includes an up/down scroll bar 114 and a right/left scroll bar 116 to allow the operator to view different portions of the document. Usually a mouse (not shown) is used to adjust the scroll bar to view different portions of the data.
Although widely accepted, this method of using screen-based scroll bars for controlling which data or portion of a document is viewed on the display at any one point in time has certain drawbacks. For example, if an operator desires to highlight or block a section of a document that spans multiple screens, the operator first positions the cursor using the mouse at the beginning of the section to be blocked. Then, by pressing and holding a button on the mouse, the operator repositions the cursor at the end of the section to be blocked. If the end of the section to be blocked is in a portion of the document that is not currently displayed on the display, the operator will have to use the mouse to move the cursor over to the up/down scroll bar to move the currently viewed section of the document up or down to the portion of the document at which the end of section to be blocked is located. At this point, and usually in conjunction with another key on the keyboard such as the SHIFT key, the operator positions the cursor at end of the section to be blocked and presses the SHIFT key simultaneously while moving the cursor to the end of the section to be blocked.
Alternatively, once the beginning of the section to be blockcd is established by moving the cursor to that point using the mouse, the cursor can be moved to the top or bottom of the screen. Once the cursor is at the top or bottom of the screen, the displayed document will automatically scroll up or down until the operator finds the end of the section to be blocked. Often, however the end of the section to be blocked is only two or three lines below the bottom of the screen. It may be difficult, however, for the operator to scroll down only two or three lines with the automatic scroll feature provided in many computers because the automatic scrolling feature usually moves through the document faster than the response time of the operator. Thus, by the time the operator stops the scrolling feature, the computer may have scrolled down one or more screen's worth of information, thereby skipping over the desired end of section of text. Further, it may be cumbersome for an operator to use the mouse to reposition the cursor within a document, and concurrently also using the mouse to scroll up and down and right and left within the document using the screen-based scroll bars.
Additionally, many operators have a keyboard tray in which the keyboard resides for easy use. The mouse, however may be located on the table or desk next to the monitor. In such situations, the operator must lean forward in an uncomfortable position to reach the mouse. Moreover, although screen-based scroll bars controlled by pointing devices such as a mouse or track ball provide an efficient technique for viewing sections of a document or data not currently displayed on a computer monitor, there are certain draw backs with such a scrolling system.